Electrical printing with ink replenishable web moving between styli and record



p 1968 w. M. BORMAN CAL PRINTING WITH INK REPLENISHABL ELECTRI WEB MOVING BETWEEN STYLI AND RECORD Flled May 4, 1964 2 Sheets-Sheet 1 Apnl 9, 1968 w. M. BORMAN ELECTRICAL PRINTING WITH INK REPLENIS WEB MOVING BETWEEN STYLI AND RECO Sheet 2 Filed May 4, 1964 United States Patent 3,377,598 ELECTRICAL PRINTING WITH INK REPLENISH- ABLE WEB MOVING BETWEEN STYLI AND RECORD William M. Borman. Niles, Ill., assiguor to Motorola, Inc., Franklin Park, 111., a corporation of Illinois Filed May 4, 1964, Ser. No. 364,734

3 Claims. (Cl. 346-74) ABSTRACT OF THE DISCLOSURE An endless belt is used to convey marking material to scanning electrode assemblies in a printer using ordinary paper. The endless belt is positioned between the electrodes and the paper. Rollers are used to convey the marking material from a supply to the belt to constantly replenish the marking material on the belt. Additional rollers may be used to enhance distribution of the marking material and one or more of the rollers may be heated to reduce the amount of solvent in the marking material after it is deposited on the belt.

Many present-day message printers used in conjunction with binary and similar information systems are provided .with an electrode assembly which scans across a moving sheet of recording paper. The electrode assembly includes a number of styli which are coupled by commutation means to decoding apparatus that supplies electrical impulses to the styli in a coded sequence and results in reproduction of characters on the recording sheet. One such printer is described in copending application Ser. No. 857,444 now Patent 3,166,752 by H. C. Waterman, filed Dec. 4, 1959, and commonly assigned.

Printers of the above type may use an electrosensitive paper of the dry burn-off type or an electrochemical paper containing a moist electrolyte. The electrosensitive' paper consists of a base layer of relatively low conductivity material with an opaque coating of contrasting semiconductive material. Discharge of electrical current from the printing styli remove localized areas of the semiconductor coating so that desired characters are outlined by exposed layers of the base material. When electrochemical paper is used, special styli of iron or stainless steel are maintained in contact with the moist paper and an electrolytic action takes place so that pigments are formed to outline desired characters.

Since printing papers of this type are expensive and often require special treatment, handling and storage, it is desirable to provide a message printer in which plain, untreated recording paper can be used. A printer using plain, untreated paper as the recording sheet is described and claimed in copending application Ser. No. 364,672, filed May 4, 1964, by H. C. Waterman, and commonly assigned. Briefly, the printer utilizes a ribbon or a webbelt impregnated with a marking material containing opaque conductive marking dyes. The ribbon or web-belt is adapted to move between the plain paper recording sheetand the printing styli during the scanning movement of the electrode assembly. Energization of selected printing styli results in current flow in the form of an electrical discharge that in turn causes relatively intense localized heating under the styli, and an explosive effect takes place to expel marking material from the ribbon or Web-belt onto the plain paper recording sheet.

It is desirable in such a printer that the marking material be continuously replenished on the ribbon or webbelt so that a new, unused area is present under the energized styli during the scanning movement of the electrode assemblies. Accordingly the present invention is particularly directed to means for applying the marking material to the moving ribbon or web-belt so that as the printing styli scan the recording sheet and move relative to the belt they are exposed to unused areas of marking material.

It is therefore among the objects of the present invention to provide an improvedmessage printer for printing characters on plain, untreated paper.

Another object is to provide, in a printer of the type utilizing electrically energized printing styli and adapted to print characters on a recording sheet, of means to continuously supply marking material to a ribbon moving between the styli and the recording sheet to enable printing of desired characters on a plain paper recording sheet.

A further object is to provide an electrical printer with improvements therein to allow direct printing on economical paper that is not required to have any special electrical or chemical properties.

A feature of the present invention is the provision, in a printer having electrically energized styli to expel marking material from an impregnated web-belt and cause it to be impinged on a plain paper recording sheet, of transfer means to continuously replenish the web-belt with the marking material.

A further feature is the provision, in a message printer of the above-described type and in which a moving webbelt having a plurality of apertures therein is impregnated with Ia marking material so that such material is conveyed in a path between the printing styli and the plain paper recording sheet, ofmeans to maintain the belt impregnated with the marking material so that a fresh supply is available as the printing styli scan the recording sheet.

Still another feature, in apparatus of the type described, is the provision of means to remove excess marking material from the web-belt and to maintain it thoroughly impregnated therewith, which means further functions to aid in conditioning the marking material prior to transport between the printing styli and the recording sheet.

Other objects, features, and attending advantages of the invention will become apparent from the following description when taken in conjunction with the drawings, in which:

FIG. 1 is an isometric view cording to the invention;

FIG. 2 is a partial cross-section taken along lines .22 of FIG. 1;

FIG. 3 is an enlarged view of one embodiment of means for applying marking material to the'web-belt; and

FIG. 4 is an enlarged view of another embodiment of means for applying marking material to the web-belt.

The message printer of the invention includes at least one scanning electrode assembly which prints complete lines of the message on a recording sheet as it scans across the sheet. The recording sheet, which is a plain paper that does not have any special electrical or chemical properties, may be fed from a roll situated in the printer and moved at approximately right angles to the traverse of the scanning electrode assemblies. The scanning electrode assemblies each include a plurality of vertically spaced styli and during each scan of the recording sheet of a message printer ac- '22 and 23. Pulleys 22 and 23 the styli are connected by a slip-bar commutator to a coding system which sequentially energizes selected styli. A ribbon or a belt comprised of a web having a large number of minute apertures therein is positioned such that it moves between the scanning electrode assemblies and the plain paper recording sheet so that the printing styli make a slight sliding contact therewith. The webbelt is impregnated with a marking material containing opaque conductive marking dyes, and energization of selected styli causes relatively intense localized heating under the styli so that an explosive effect takes place to produce an overpressure that expels marking material from the web-belt and impinges it on'the recording paper in the form of a dot.

The marking material may conveniently include a vinyl resin, with a suitable plasticizer, that serves as a hinder or substrate, and further contains finely divided conductive particles such as graphite or carbon to impart a finite resistivity thereto and to provide acontrasting dot when impinged on the recording sheet. Alternately the binder may contain the solvent which is sufficiently volatile so that it evaporates to provide a semi-solid coating of the marking material on the belt at ambient temperatures.

In order to replenish the marking material on the webbelt, there is provided a pliable vessel or container having a restricted opening and which is maintained under pressure to apply the marking material to a transfer roll. The web-belt is continuously passed between and in contact with an applicator roller and a back-up roller, with the applicator roller coacting with the transfer roller so that the marking material is continuously applied to the web-belt. The web-belt further moves through a pair of sizing rollers that function to remove excess marking material and to thoroughly impregnate it with the marking material, and to aid in conditioning the surface of the belt once the marking material has been applied.

Where the marking material contains a plasticized vinyl resin which is in a semi-solid state at room temperatures, heat is applied to the vessel which stores the marking material so that it becomes sufficiently viscous for transfer by roller to the web-belt. The sizing rollers further contain heat radiating fins which aid in reducing the temperature of the marking material to ambient so that it is more readily returned to a semi-solid state. In instances where the marking material contains a solvent and is in a liquid state in the storage vessel, heat may be applied to the sizing rollers to facilitate evaporation so that the coating on the web-belt has the desired surface conditions.

In a further embodiment the marking material is conveyed from a transfer roller to the belt by way of an intermediate applicator belt. The applicator belt picks up marking material from the transfer roller and applies it to the marking belt. This arrangement allows the storage vessel for the marking material to be more conveniently located on the printer.

Referring to FIG. 1, numeral 10 indicates a sheet of plain paper which may be conveniently stored on roller 12. Paper 10 passes between guide roller 14 and pressure roller 16, and is advanced over a metal backing plate 18. A drive roller (not shown for simplicity of the drawing) and suitable idler rollers may be located above backing plate 18 to provide advancement of the paper. The drive roller in turn is coupled by suitable gearing and pulley arrangements to a drive motor to cause paper 10 to move vertically past backing plate 18. Paper drive arrangements of this type are known in the art and may be, for example, of the type described in the aforesaid copending application Ser. No. 857,444.

A plurality of scanning electrode units 20 are secured to horizontally disposed belt 21, looped around pulleys in turn are arranged to carry electrode assemblies 20 in a horizontal path between paper 10 and slip bar commutator 24. Slip-bar commutator 24 is positioned above belt 21 and in front of paper 10 by suitable brackets (not shown). Pulley 22 is supported on shaft 27 and driven by shaft 28 through gearing arrangement 29. Shaft 28, in turn, is coupled to the drive motor which advances paper 10 so that as paper 10 is moved vertically across backing plate 18, it is also scanned by electrode assembly 20. Pulley 23 functions as an idler.

Each electrode assembly 20 includes a plurality of vertically spaced conductive electrodes, each having a number of vertically positioned marking styli 20a, and each further having finger portions 20b. Marking styli 20a are directed towards and adapted to be in sliding contact with web-belt 30. Electrode finger portions 20b are directed towards and adapted to be sliding contact with the side of slip bar commutator 24 that faces paper 10, which side contains a plurality of horizontally disposed, insulatingly spaced conducting grooves 26 (FIG. 2) adapted to make electrical contact with electrode finger portions 2%. Electrode assemblies 20 are carried horizontally between paper 10 and slip bar commutator 24 so that electrode finger portions 20b are in electrical contact with conducting grooves 26 during scan of paper 10. Electrical impulses are selectively applied to individual conductors 25 on the back side of slip-bar commutator 24. Each conductor 25 completes an electrical circuit with a respective one of conducting grooves 26. Conductors 25 and conducting grooves 26 may be formed on slip-bar commutator 24 by plating or similar techniques. Details of the manner in which the electrode assemblies 20 are energized by impulses applied to slipbar commutator 24 and the manner in which slip-bar commutator 24 supplies the impulses to electrode assemblies 20 in response to a received binary code are fully set forth in copending application Ser. No. 857,444. As therein described, this arrangement provides a printing unit wherein the scanning electrode assemblies print complet lines of a message as a recording medium such as paper 10 is scanned by electrode assemblies 20.

In order to provide printing on plain, untreated paper and in accordance with the techniques set forth in copending application Ser. No. 364,672, web-belt 30 is looped around pulleys 32 and 33 and is positioned to pass over paper 10 immediately opposite styli 20a of electrode assemblies 20 as paper 10 is scanned by electrode assemblies 20. Web-belt 30 is maintained in sliding contact with or positioned a very slight distance from paper 10. Pulley 32 is supported on shaft 34 and shaft 34 is in turn driven from shaft 27 by the gearing arrangement 35. Gearing arrangement 35 is adapted to drive pulley 32 concurrently with pulley 22 but in an opposite direction, as shown by the arrows of FIG. 1. This causes web-belt 30 to move across paper 10 in the same direction as electrode assemblies 20. In addition, gearing arrangement 35 between shafts 34 and 27 is adapted to drive pulley 32 at a slower speed than pulley 22.

Web-belt 30 conveys a marking material containing carbon particles between styli 20a and paper 10 as it is revolved by pulley 32. When selected marking styli are supplied with an electrical impulse resulting current flow through the web-belt 30 causes a small dot of marking material to be impinged on paper 10. The dot is opaque and when coded impulses are supplied to electrode assemblies 20 by slip-bar commutator 24 the desired characters are formed on paper 10.

Web-belt 30 contains a plurality of apertures to provide a fine mesh. In order to produce localized coherent dots on paper 10, the apertures in web-belt 30 should be small with respect to the diameter of an energized stylus so that there are several apertures for one stylus diameter. For example, for a .008 inch diameter tungsten stylus, a -300 mesh screen should be used for web-belt 30. To provide this fine mesh web-belt 30 may be woven from strands or organic or synthetic fibers such as silk, nylon, fiberglass and various polyester and acrylic materials. Alternately, web-belt 30 may be woven from metallic strands (and anodized where an insulated web belt is desired), or may be fabricated by etching a thin metal sheet by known chemical milling or etching techniques.

Web-belt 30, as has been noted, is driven by pulley 32 to move across paper in the same direction as scanning motion of electrode assembly 20. Web-belt is also recharged or replenished with marking material as it revolves. Gearing arrangement 35 is adapted to drive web-belt 30 at a slower relative speed, as for example, one-half the speed of electrode assemblies 20 carried by belt 21. This allows each electrode assembly to scan.

across a fresh area of marking material on web-belt 30 during this printing of each line on paper 10.

The marking material to be applied to web-belt 30 may be a paste or wax-like binder containing graphite and carbon black, or may be a solvent containing atomized wax, graphite and carbon black. The former type marking material may include, for example, a blend of thermoplastic resins such as vinyl resins, parafiin wax,

and a plasticizer such as chlorinated polyphenyl. The

latter type marking material may include atomized wax, a carboxy vinyl polymer or a water soluble alkyd resin, and graphite and carbon black, mixed with a volatile solvent or water to provide the desired viscosity.

To apply marking material to web-belt 30, and in accordance with the present invention, there is provided an intermediate transport roller or belt to convey the marking material from a storage vessel to a pair of applicator and back-up rollers through which the webbelt 30 passes. With particular reference to FIG. 3, webbelt 30 passes between applicator roller and backup roller 42. Intermediate transport roller 44 carries marking material from storage vessel 46 to applicator roller 40. Storage vessel 46 is a pliable container maintained under pressure by compressor shoes 47 and 49 so that the semi-solid marking material is expelled through a slit aperture 48 and onto transport roller 44. Rod 50, having one end 52 thereof threaded, is threadably engaged with internally threaded bores extending through compressor shoes 47 and 49. This enables pressure to be applied to storage vessel 46 by a vise-like action.

Where the marking material contains a thermoplastic resin and a low temperature plasticizer, application to web-belt 30 is facilitated by maintaining it at slightly elevated temperature (for example 7075 C.) in storage vessel 46. This may be accomplished by heating compressor shoes 47 and 49 as, for example, by making rod 50 hollow and inserting an electrical heater unit therein. Alternately, electrical grid heaters may be disposed on the faces of compressor shoes 47 and 49.

After the marking material has been conveyed between storage vessel 46 and applicator roller 40 by transport roller 44 to be thereby applied to web-belt 30 as it passes between rollers 40 and 42, web-belt 30 further passes between sizing rollers 54 and 56. Sizing rollers 54 and 56, which are of highly thermal conducting metal, function to remove excess marking material from web-belt 30 and provide a smooth, non-tacky surface. Where the binder for the marking material contains a thermoplastic resin that has been heated above ambient temperature, radiating fins 58 may be secured to the shaft which supports rollers 54 and 56 to enhance cooling. Alternately, where the marking material contains a volatile solvent, radiating pins 58 may be replaced by electrical heaters to heat sizing rollers 54 and 56 to assist in driving off the solvent.

With particular reference now to FIG. 4, the marking material may be conveyed to web-belt 30 by an auxiliary transport belt 63, which passes around rollers 60 and compresses web-belt 30 against back up rollers 62. Transport belt 63 is looped around roller 66 and passes over roller 64. A further transport roller 68 is disposed in storage vessel 70, containing a quantity of marking material, and adapted to apply the marking material to con- 6 veyor belt 63. By maintaining pressure between rollers 60 and 62, belt 63 moves concurrentlywith the movement of web-belt 30. As in the case of the embodiment of FIG. 3, the marking material in storage vessel 70 may be heated slightly above ambient and subsequently cooled by sizing rollers 56 and 54 and radiating pins 58. The arrangement of FIG. 3 allows the storage vessel for the marking material to be located remotely from web-belt 30 for flexibility of printer installation.

I claim: 1. In a printer for use with a plain paper recording sheet, which printer includes means for moving at least one electrode assembly having a plurality of printing styli across the recording sheet and a belt positioned to move between said styli and said recording sheet, with said belt having a plurality of apertures therein and impregnated with a marking material which presents a surface to said styli so that localized areas thereof are impinged upon said recording sheet upon energization of said styli with electrical impulses, the combination including a pliable vessel having a restricted openin for storing a quantity of said marking material, first and second rollers positioned on opposite sides of said belt and in contact therewith, a third roller positioned to be in contact with one of said first and second rollers and adapted to transport marking material thereto, and means to apply pressure to said pliable vessel to thereby eject said marking material onto said third roller, whereby said marking material is applied to said belt by said rollers.

2. In a printer for use with a plain paper recording sheet, which printer includes means for moving at least one electrode assembly having a plurality of printing styli across the recording sheet and a belt positioned to move continuously between said styli and said recording sheet,

' with said belt having a plurality of apertures therein and impregnated with a plasticized semi-solid marking material, the combination including a pliable vessel having a restricted opening for storing a quantity of said marking material, first and second rollers positioned on opposite sides of said belt and providing contact therewith, a third roller positioned to transport said marking material from said vessel to one of said first and second rollers, means for applying pressure to said vessel to thereby expel marking material onto said third roller, means for applying heat to said vessel to thereby maintain said marking material in a viscous condition during storage, and fourth and fifth rollers positioned on opposite sides of said belt and maintained in contact therewith, said fourth and fifth rollers each having heat radiating means integral therewith, whereby marking material is continuously applied to said belt by'said first and second rollers and is conditioned to provide a smooth semi-solid surface on said belt by said fourth and fifth rollers.

3. In a printer for use with a paper recording sheet, which printer includes means for moving at least one electrode assembly having a plurality of printing styli across the recording sheet, a belt positioned to move continuously between said styli and said recording sheet, with said belt having a plurality of apertures therein and impregnated with a marking material, the combination including a pliable vessel for storing said marking material, first and second rollers disposed on each side of said belt and in contact therewith, a third roller in contact with one of said first andsecond rollers and positioned to convey marking material from said vessel to said one of first and second rollers, means to apply pressure to said vessel to eject marking material therefrom, fourth and fifth rollers positioned on opposite sides of said belt and in contact therewith, means to apply heat to said fourth and fifth rollers to condition said marking material to thereby provide a smooth semi-solid surface of marking material on said belt to be carried between said styli and said recording sheet, whereby marking material is continuously applied to said belt.

(References on following page) References Cited UNITED STATES PATENTS Pnllen 197-171 Dixon 197171 Dalton 101426 Gundlach 34674 8 3,166,752 1/1965 Waterman 34674 3,182,591 5/1965 Carlson 34674 3,234,904 2/1966 Van Wagner 101-426 5 BERNARD KONICK, Primary Examiner. 

